In this Article

• What is an electromyogram?
• Why is an EMG test done?
• How is an intramuscular EMG done?
• How do you prepare for an intramuscular EMG?
• Does an EMG hurt?
• What other test is done during an intramuscular EMG?
• Electromyogram Index

How do you prepare for an intramuscular EMG?

For adults, no special preparation is needed. For infants and children, the physical and psychological preparation depends on the child's age, behavior, and prior experience. (For instance, has the child been traumatized by another medical or dental procedure?)

Does an EMG hurt?

Yes. There is some discomfort at the time the needle electrodes are inserted. They feel like shots (intramuscular injections), although nothing is injected during an EMG. Afterwards, the muscle may feel a little sore for up to a few days.

What other test is done during an intramuscular EMG?

A nerve conduction velocity (NCV) test is often done at the same time as an EMG. In this test, the nerve is electrically stimulated while a second electrode detects the electrical impulse 'down-stream' from the first. This is usually done with surface patch electrodes (they are similar to those used for an electrocardiogram) that are placed on the skin over the nerve at various locations. One electrode stimulates the nerve with a very mild electrical impulse. The resulting electrical activity is recorded by the other electrodes. The distance between electrodes and the time it takes for electrical impulses to travel between electrodes are used to calculate the speed of impulse transmission (nerve conduction velocity). A decreased speed of transmission indicates nerve disease.

The NCV test can be used to detect true nerve disorders (such as neuropathy) or conditions whereby muscles are affected by nerve injury (such as carpal tunnel syndrome). Normal body temperature must be maintained for the NCV test, because low body temperatures slow nerve conduction.

Previous contributing authors and editors:

Medical Author: Frederick Hecht, MD, FAAP, FACMG
Medical Editor: Barbara K. Hecht, Ph.D.

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